Substantial and mounting evidence suggest that blood flow mechanics (hemodynamics) play a leading role in the development and progression of abdominal aortic aneurysm (AAA) disease. Correspondingly, it is hypoth- esized that increased blood flow through AAA due to exercise may provide an effective means to slow or halt disease progression. Precise understandings of realistic AAA hemodynamics are lacking. The objective of this project is to use innovative computational dynamical systems methods for fluid flow structure analysis to under- stand the specific nature of how blood is transported through AAA, and furthermore, to use this framework to evaluate how flow conditions change from rest to exercise. A synergistic collaboration with the National Center for Biomedical Computing at Stanford, Simbios, is proposed, which leverages expertise at the Illinois Institute of Technology (IIT) in the characterization and analysis of complex transport phenomena with the blood flow simula- tion capabilities and unprecedented wealth of AAA hemodynamics data being generated at Stanford. Simbios will provide AAA blood flow simulation data for patients with small and intermediate sized AAA, and necessary data to reproduce the simulation results, to investigators at IIT, who will use the data to apply computational dynamical systems methods to more precisely characterize transport conditions in the aneurysm. For each patient, the detailed flow structure information resulting from the dynamical systems computations will be compared between rest and exercise conditions to evaluate the biomechanical benefits of acute exercise on AAA hemodynamics. This information will be combined with follow-up images of each aneurysm's progression for prospective clinical correlation to establish the relevance of our findings, and to potentially uncover the biomechanical mechanisms underlying AAA progression. PUBLIC HEALTH RELEVANCE: Abdominal aortic aneurysm (AAA) is a common and morbid disease that garners little public attention. Evi- dence suggests that the nature of blood flow in the abdominal aorta is largely responsible for AAA initiation and progression. We aim to use novel computational techniques to study blood flow patterns in AAA. The more we learn about the mechanisms underlying AAA pathology, the better equipped we will be to prevent, diagnose and less-invasively treat this devastating disease.